 Dirofilaria immitis Christina Drazan

Taxonomy  D. repens  Subcutaneous in dogs  In humans  manifests as either a wandering worm in the subcutaneous tissue or granulomatous nodule  D. tenuis  Subcutaneous in raccoons  In humans  wondering worm  D. ursi  Subcutaneous in bears  Again in humans  wondering worm

Hosts  Definitive host: dogs  Accidental hosts: foxes, wolves, coyotes, cats, ferrets, sea lions  Intermediate host: over 70 species of mosquitoes

Geographic Distribution

Morphology  Adults are long, white, thread-like worms  Females are 25 to 30 cm long  Males 12 to 16 cm long with spirally coiled tail

Life Cycle

 resources/canine.html resources/canine.html

Pathogenesis  Inflammation and thickening of the heart  Insufficient respiration, Chronic cough, Vomiting  It can be fatal  Symptoms appear when more than 25 worms are present  ≤60 worms causes circulatory problems  ≥100 worms, there is blockage of the pulmonary artery and right side of the heart, accompanied by interference with the actions of the heart valves  Right side become dilated and enlarged  Blood backs up in the liver and other parts of the body  Rarely survive

Diagnosis  Accurate patient history  Recognition of varied clinical signs  X-ray  Angiography  Ultrasound  ELISA testing for antigens secreted by female worms  Microfilarial detection and differentiation in blood smears  Necropsy examination

Treatment  Adulticide  Milarsomine dihydrochloride  Thiacetarsemide  Microfilaricide  Milbemycin oxime  Are toxic so careful observation is required after administration  Aren’t used until side effects from the adulticide are fully gone

Public Health Concerns  It can infect humans  Subcutaneous nodules or in the lungs  Commonly labeled as malignant tumors which require invasive investigation and surgery before being correctly diagnosed

Control  Prevention  Topical  Oral